A CA (carrier aggregation) characteristic is introduced in LTE (long term evolution) version 10, so that multiple cells may simultaneously provide a data transmission service for one UE (, user equipment). To simultaneously obtain radio channel states of the multiple cells, an eNB (evolved Node B, evolved base station or node B) relies on measurement of the user equipment on channels of the multiple cells, and then CSI (channel state information) is fed back to the base station, based on which the base station performs scheduling.
For downlink performance, discarding CSI seriously affects downlink scheduling, including selection of a downlink mode and selection of a transmission layer and a pre-coding and modulation and coding scheme, so that the downlink performance is affected due to lack of reporting channel information. In the prior art, the base station performs pre-configuration through higher layer signaling, to notify the user equipment that which format is adopted to feed back CSI. The prior art may solve the problem that the downlink scheduling is seriously affected when multiple pieces of CSI simultaneously occur in one sub-frame and a pieces of CSI with a low priority level is discarded, but cannot flexibly allocate resources fed back in a CSI period, thereby resulting in low use efficiency of channel resources.